Hi Simon!

You are making a good point: there are different levels of
"accessibility" when it comes to inputs:

- The source.
- The explicit inputs.
- the implicit inputs.
- The build inputs.
- The build system inputs.
- Recursive inputs.
- ...?

Which one should we expose?  I don't know.  If we want the system to
have some set of properties, I guess only the resulting packages matther
and the build inputs don't.

Should we touch implicit inputs, we would have to parse all the
references and not just the explicit inputs like --with-input does.

> but be able to
> recompile a matrix of combinaison would be really cool!

Indeed.  But now I'm starting to wonder if it is really doable :p

-- 
Pierre Neidhardt
https://ambrevar.xyz/